1. Field of the Invention
This invention relates in general to RKE systems, and more specifically, RKE system using multi-channel communications.
2. Background of Related Art
Remote vehicle entry transmitters/receivers are used for performing a wireless operation on a vehicle such as locking and unlocking a vehicle door, unlatching a trunk latch, or activating or deactivating an alarm system equipped on the vehicle. This remote entry device is commonly referred to a remote keyless entry (RKE) fob. The RKE fob is typically a small rectangular or oval plastic housing with a plurality of depressible buttons for activating each one of the wireless operations. The RKE fob is carried with the operator of a vehicle and can wirelessly perform these functions when within a predetermined reception range of the vehicle.
The RKE fob communicates with an electronic control module within the vehicle via a RF communication signal. The operator, when positioned outside of the vehicle, depresses one of the buttons on the RKE fob which broadcasts a wireless signal that is received by the electronic control module when the RKE fob is within a broadcasting range of the vehicle. The electronic communication module upon receiving the broadcast signal authenticates the signal and performs the requested keyless entry function if the signal is validated.
The receiver of the RKE electronic control module may experience interference from other communication modules within the vehicle system such as a tire pressure monitoring (TPM) system. A TPM system disposes pressure sensors on or within vehicle tires to sense the pressure within a respective tire and report low or high pressure conditions to a driver. TPM systems sense tire pressure within a tire and transmit a signal to a body-mounted receiving unit located external to the tire for processing tire pressure data. Interference may occur when the signal transmitted by the transmitting devices of TPM system is broadcast in the same operating frequency of the RKE receiver.
Multiple communication channels may be used to transmit between the electronic control module and the RKE fob; however, power consumption is an issue if the receiver is required to dwell on all channels waiting for a signal to be broadcast. This will increase in the power consumption and the “on time” of the receiver in the electronic control module to monitor for the signal on all channels. This extended time period to search all channels and determine if a signal is present increases the quiescent current of the receiver and therefore cause a drain on the vehicle power supply system.